An artificial safe passage of downward mining and a construction method thereof

Abstract

The application discloses a downward mining artificial false lane safety channel and a construction method thereof, and belongs to the technical field of underground mine exploitation and safety engineering. A semi-permanent safety channel is constructed in a stope in advance before filling at a position close to a lower disc. The channel is connected by a horizontal artificial false lane at a first mining layer and vertical steel cylinders vertically penetrating all intermediate layers from the false lane. A steel cylinder at a suitable position is constructed before false bottom construction, the horizontal artificial false lane is constructed after the false bottom is made, and the vertical steel cylinders are connected in sections by welding after each subsequent layer is mined and before filling. Ladders are arranged in the steel cylinders, and finally a safety channel is formed from the first layer to all the following layers, which is used as a second safety outlet and air return roadway of the stope. The application has the advantages of good mining process coordination, reliable structure, low cost, and significant improvement of the intrinsic safety level of the stope.

Description

Technical Field

[0001] This invention relates to a safety passage for a stope in the downfill mining method and its construction method, belonging to the field of underground mining technology. Background Technology

[0002] Downward backfilling is an important method for mining fractured, high-value ore bodies. This method involves layered mining from top to bottom, with backfilling immediately after each layer is mined. However, this method has a significant safety hazard: the stope typically has only one formal exit connected to the upper middle section via a ramp or raise. If this exit becomes blocked, workers in the stope will lack an emergency escape route. Furthermore, a single exit limits the stope's ventilation capacity. Current technologies typically employ dedicated drainage and ventilation wells or utilize boreholes as auxiliary passages, but these methods are either labor-intensive and costly, or have small cross-sections and limited functionality, making them unreliable as safe pedestrian passages. Therefore, there is an urgent need for a safety passage construction technology that can work in conjunction with downward backfilling, has a simple and reliable structure, and combines pedestrian escape and ventilation functions. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of existing downfill mining methods, such as the single safety exit and lack of dedicated emergency escape and efficient ventilation passages, and to provide a semi-permanent artificial false tunnel safety passage that is closely integrated with and constructed synchronously with the mining backfilling process, as well as its construction method.

[0004] The technical solution of this invention is as follows: A downward-facing artificial false tunnel safety passage includes a horizontal artificial false tunnel constructed within the upper backfill of the first mining layer and a vertical steel cylinder extending downwards from the false tunnel and penetrating each intermediate layer, the two being interconnected. The horizontal artificial false tunnel is constructed on the upper side of the artificial false bottom and includes retaining walls, H-beams as the main support structure, channel steel for longitudinally connecting adjacent H-beams to enhance overall stability, steel pads placed at the bottom of the H-beams, triangular steel plates for reinforcing the arch corners, and back plates and round logs for preventing backfill slurry from flowing into the false tunnel. The back plate is attached to the sidewall of the tunnel as the main isolation layer, and the round logs are wedged between the back plate and the backfill to stabilize the back plate. The vertical steel cylinder is mainly composed of welded steel cylinders connected in sections, and a pedestrian ladder for personnel passage is fixed to the inner wall of the steel cylinder. The steel cylinder is enclosed by the artificial false bottom and the backfill.

[0005] Preferably, the retaining wall is located at the end of the artificial alley; the I-beams are erected on the artificial base at preset intervals.

[0006] Preferably, the artificial false bottom is made of poured concrete; the steel cylinder is connected section by section in each layer by welding or flanges.

[0007] A method for constructing a safety passage for a downward mining artificial tunnel involves first back-mining and filling the adjacent access roads on both sides of the artificial tunnel within the first mining layer, so that a stable filling body is formed on both sides. Then, the access road where the artificial tunnel is located is back-mined, and a horizontal artificial tunnel is constructed within the access road with a reserved vertical steel cylinder interface. In subsequent layers, the steel cylinders are connected downwards segment by segment with the mining-filling cycle, eventually forming a through safety passage.

[0008] Preferably, the horizontal artificial alleyway includes retaining walls, I-beams, channel steel, steel base plates, triangular steel plates, back plates, and round logs.

[0009] Preferably, the method includes the following specific steps: S1: In the first mining layer, the adjacent access roads on both sides of the false roadway are mined and filled first. After the filling body on both sides reaches the design strength, the access roadway where the false roadway is located is mined. The first section of steel cylinder is erected at the designed position in the access roadway. A crushed ore cushion layer is laid at the bottom of the stope and a plastic film is laid. Then, an artificial false bottom is constructed. After the artificial false bottom is cured, a retaining wall is constructed on the side of the steel cylinder near the upper plate of the stope. The height of the steel cylinder in the middle section of the first mining layer is greater than the sum of the thickness of the artificial false bottom and the thickness of the crushed ore cushion layer. S2: On the artificial false bottom, install side and top I-beams at the designed spacing, install steel pads at the bottom of the I-beams to improve stability, add back plates on both sides and fill them with round logs for stability, install channel steel between the side I-beams, and place back plates and round logs on the top plate of the I-beams. S3: Complete the overall filling of this layer to form a filling body that encloses the false alley and steel cylinder; S4: Proceed to the next layer of mining, exposing the lower end of the steel cylinder reserved in the previous layer, and reserve a movable ladder to connect to the safety exit; S5: After the mining is completed, clean the working face, connect and fix the new steel cylinder of this section to the steel cylinder of the previous section, lay a crushed ore cushion layer at the bottom of the mining area, lay a plastic film, and then fill it; S6: Repeat steps S4-S5 until the steel cylinder extends to the bottom layer.

[0010] Preferably, as each section of the steel cylinder is connected and fixed, a corresponding pedestrian ladder is simultaneously installed on the inner wall of that section of the steel cylinder, connecting layer by layer with the previous section of the ladder.

[0011] Preferably, the welding and pre-reservation of the steel cylinder for each layer are completed before the filling construction of each layer. After filling, the lower end interface is located in the crushed ore cushion layer. When the roof is exposed during the mining of the lower layer of ore body, the interface is exposed for 20-30cm.

[0012] The core of this invention lies in constructing a horizontal artificial tunnel as the entrance and starting point of the passage at the first mining layer. Starting from this point, the passage extends downwards layer by layer through the welding of vertical steel cylinders in sections, eventually penetrating all intermediate layers and reaching the bottom layer. The horizontal artificial tunnel serves as the initial stable section of the passage, while the vertical pipe serves as the passageway penetrating the main structure; the two connect to form a complete vertical shaft-type safety passage. The horizontal artificial tunnel uses I-beams as its framework, reinforced with triangular steel plates at the arch corners, and has a backing plate on the outside as the main isolation layer, further stabilized with round logs. Channel steel longitudinally connects adjacent I-beams to enhance overall stability. The vertical pipe is constructed from standard-diameter steel cylinders welded in sections, extending segment by segment as the passage descends. Pedestrian ladders are simultaneously welded into each steel cylinder section, allowing the ladders to connect layer by layer as the passage extends. At the current mining layer, movable ladders are used to meet the pedestrian needs of the passage.

[0013] The beneficial effects of this invention include: First, it offers outstanding safety benefits: it provides an independent, reliable, and permanent second safety exit for the downward mining area, greatly increasing the probability of emergency escape.

[0014] Secondly, improved ventilation: This channel can be used as a return air shaft, forming an effective through airflow, which significantly improves the working environment in deep mining areas.

[0015] Third, the process has good synergy: the construction of the channel is fully integrated into the standard cycle of downward mining-backfilling, which is convenient for construction and has little impact on normal production.

[0016] Fourth, the structure is economical and reliable: only I-beams are used for support on the first floor, and steel cylinders are used for extensions thereafter, which is significantly cheaper than excavating a special rock shaft.

[0017] Fifth, integrated functions: It integrates safety escape, ventilation and pedestrian access, with high comprehensive benefits. The ladder is installed section by section with the steel cylinder. The construction process is highly synchronized with the mining cycle, without the need for additional procedures, resulting in high comprehensive benefits. Attached Figure Description

[0018] Figure 1 This is a cross-sectional schematic diagram of an embodiment of the artificial false alleyway safety passage constructed by the present invention.

[0019] Figure 2 yes Figure 1 BB cross-sectional diagram.

[0020] Figure 3 yes Figure 2 A schematic diagram of the AA cross-section.

[0021] Figure 4 yes Figure 1 A schematic diagram of the CC cross-section.

[0022] Figure 5 This is a schematic diagram of the pedestrian ladder arrangement in an embodiment of the artificial alleyway safety passage of the present invention.

[0023] Explanation of reference numerals in the attached drawings: 1. Filling material; 2. Retaining wall; 3. I-beam; 4. Channel steel; 5. Steel base plate; 6. Round log; 7. Artificial false bottom; 8. Crushed ore cushion layer; 9. Steel cylinder; 10. Plastic film; 11. Pedestrian ladder; 12. Triangular steel plate; 13. Back plate. Detailed Implementation

[0024] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0025] A gold mine employs the downward horizontal approach backfilling mining method. The mine extends north to line 135 and south to line 141. The ore body is vein I, hosted in pyrite-sericite and pyrite-sericite-quartzized breccia in the footwall of the main fault. Its occurrence is largely consistent with the main fault, striking at 30°–50° and dipping north-west at 27°–30°. Due to the influence of tectonic structures and joints, the rock stability is classified as Class IV, indicating fractured rock that is prone to damage. The hydrogeological conditions are simple, primarily characterized by surface seepage. This mine utilizes the downward mining artificial false tunnel safety passage and its construction method provided by this invention to construct a safety passage within the connecting roadway near the footwall area. The steps include: (1) Layout of the mining area and construction of the first mining layer The stope is divided into four layers, arranged vertically, parallel, and staggered. The first layer (first layer) has a designed mining width of 3.5m, a mining height of 3.5m, and an access road of 3.5m x 3.5m, perpendicular to the strike of the ore body. The connecting roadway of the stope is also designed to be 3.5m x 3.5m. To ensure the stability of the artificial tunnel, this layer adopts a construction sequence of "filling the sides first, then mining the middle": first, the adjacent access roads on both sides of the artificial tunnel are mined, and the access roads on both sides are cemented and filled. After the filling on both sides reaches the design strength, the access roadway containing the artificial tunnel in the middle is mined. After the access roadway containing the artificial tunnel is mined, a location is selected in the connecting roadway of the stope near the footwall area as the entrance location for the safe passage of the artificial tunnel.

[0026] (2) Construction of the first layered artificial tunnel and the first section of steel cylinder like Figure 1At the selected passage location, the first section of steel cylinder 9 is erected. Steel cylinder 9 is made of Q235 steel pipe, with a diameter of 1.0m, a wall thickness of 6mm, and a height of 1.0m (this height must be greater than the sum of the 0.6m thickness of the false bottom and the 0.2m thickness of the crushed ore bedding layer). After leveling, a crushed ore bedding layer 8 is laid, with a thickness of not less than 200mm. A plastic film 10 is laid on top of the crushed ore bedding layer 8, and a layer of wooden blocks (used to elevate the reinforcing mesh) is placed on top of the plastic film 10, and a bottom reinforcing mesh is woven and welded. Subsequently, the false bottom is filled with C30 concrete, constructing an artificial false bottom 7 with a height of 0.6m. After the artificial false bottom 7 has cured for 3 days, a retaining wall 2 is constructed on the side of steel cylinder 9 near the upper plate of the stope. The retaining wall 2 is 1.2m wide and 0.3m thick. Figure 2 , Figure 3 and Figure 4 I-beams 3, preferably #16, are erected on both sides of retaining wall 2, extending to the outer entrance of the stope. Channel steel 4, preferably #8, is longitudinally connected between adjacent vertical I-beams 3. Since both sides are already filled with stable backfill, the sidewalls of the false roadway will not be subsequently mined, thus the backplate 13 and logs 6 will not be disturbed by the mining of adjacent roads. Triangular steel plates 12 are welded at the arched corners of the I-beams 3 and channel steel 4. These plates are made of Q235 steel plate, with dimensions of 200mm × 200mm × 10mm, and are used to enhance node rigidity. Backplates 13, made of wood with a thickness of not less than 30mm, are laid on the outside of the I-beams 3, tightly fitted between the I-beams 3 and the roadway sidewalls, serving as the main isolation layer to prevent the backfill slurry from flowing in. After the backing plate 13 is laid, round logs 6 are wedged between the backing plate 13 and the filling body 1. The round logs 6 are made of round pine wood with a diameter of not less than 120mm, used to fix the backing plate and enhance overall stability, ensuring the sealing effect. After the installation is completed, upper adhesive filling is carried out with a filling ratio of 1:6, forming the filling body 1 that encloses the artificial tunnel. After this layered filling is completed, a horizontal artificial tunnel entrance and the first section of the vertical steel cylinder 9 are formed. Figure 5 The first section of the pedestrian ladder 11 is welded to the inner wall of the steel cylinder 9. The ladder is made of φ16mm round steel, with a width of 400mm and a step spacing of 300mm. The height of the first section of the ladder is the same as that of the steel cylinder 9.

[0027] (3) Second layer of steel cylinder extension The second-level mining access road has a specification of 4.0m × 3.8m. Adjacent level access roads are arranged in parallel, perpendicular and staggered positions, with one access road every two levels. After the first-level steel cylinder 9 is exposed, one can enter the steel cylinder through the pedestrian ladder 11 and climb to the artificial false roadway of the first mining level as a temporary safety exit.

[0028] After the second layer of mining was completed, the crushed ore in the crushed ore cushion layer 8 fell, exposing the bottom of the steel cylinder 9 reserved in the first layer, with an exposed length of approximately 200mm. After cleaning the working face, the new steel cylinder 9 of this layer (the new steel cylinder 9 of this layer is made of Q235 steel pipe, with a diameter of 1.0m, a wall thickness of 6mm, and a height of 4m) was joined to the previous steel cylinder 9 and fixed by welding. The weld was full to ensure structural strength, and a pedestrian ladder 11 was welded to the inner wall simultaneously. A crushed ore cushion layer 8 with a thickness of 200mm was laid at the bottom of the extended steel cylinder 9. Then, the false bottom construction and the upper cemented backfilling work were repeated.

[0029] (4) Extension of the third layer of steel cylinder Repeat step (3). After the third layer of mining is completed, continue to extend the steel cylinder 9. The height of the steel cylinder 9 is the same as the height of the new steel cylinder in the previous layer. After extension, lay the crushed ore cushion layer 8, wrap it with plastic film 10, and carry out backfilling operations.

[0030] (5) Extension of steel cylinders in the fourth and subsequent layers Repeat step (3) to complete the extension of the layered steel cylinder. After all mining sites are completed, filling can be carried out directly.

[0031] The following examples illustrate the function of the channel of the present invention and its effect in the field.

[0032] This artificial false tunnel serves as the second safety exit of the mining area, and also functions as a dedicated return air shaft and pedestrian inspection passage. The main safety exit of the mining area is the connecting roadway leading up to the surface via ramp #2. The second safety exit is the artificial false tunnel leading to the section roadway via the preparation ramp, and then up to the surface via ramp #1. The air velocity within the tunnel is controlled at 0.5~1.0 m / s, effectively improving the ventilation conditions of the mining area.

[0033] After adopting this invention, the number of safety exits in the stope increased from one to two, significantly improving emergency escape capabilities. The tunnel construction process is fully coordinated with the downward mining-backfilling process, minimizing disruption to normal production. As a dedicated return air shaft, the tunnel increases the return air volume in the stope by approximately 30%, reduces the working face temperature by 2-3°C, and significantly improves the working environment. The ladders for pedestrians within the tunnel are sturdy and reliable, meeting the needs of daily inspections and emergency escape.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A safety passage for a downward mining artificial tunnel, characterized in that: It includes a horizontal artificial false tunnel constructed within the upper filling body (1) of the first mining layer and a vertical steel cylinder extending vertically downward from the false tunnel and penetrating each intermediate layer, the two being interconnected; the horizontal artificial false tunnel is constructed on the upper side of the artificial false bottom (7) and includes a retaining wall (2), an I-beam (3) serving as the main support structure, a channel steel (4) used to longitudinally connect adjacent I-beams to enhance overall stability, a steel pad (5) set at the bottom of the I-beam (3), and triangular steel used to reinforce the arch corners. The backing plate (12) and the backing plate (13) and the log (6) used to prevent the filling slurry from flowing into the false tunnel; wherein the backing plate (13) is attached to the side wall of the tunnel as the main isolation layer, and the log (6) is wedged between the backing plate (13) and the filling body to stabilize the backing plate (13); the vertical steel cylinder is mainly composed of welded steel cylinders (9) connected in sections, and the inner wall of the steel cylinder (9) is fixed with a pedestrian ladder (11) for personnel to pass through; the steel cylinder (9) is wrapped by an artificial false bottom (7) and the filling body (1).

2. The safety passage for downward mining artificial tunnels according to claim 1, characterized in that: The retaining wall (2) is located at the end of the false alley; the I-beam (3) is erected on the artificial false bottom (7) at a preset interval.

3. The safety passage for downward mining artificial tunnels according to claim 1, characterized in that: The artificial false bottom (7) is made of concrete; the steel cylinder (9) is connected section by section by welding or flange in each layer.

4. A method for constructing a safety passage in a downward mining artificial tunnel, characterized in that: In the first mining layer, the adjacent access roads on both sides of the false tunnel are mined and filled first, so that a stable filling body is formed on both sides. Then the access road where the false tunnel is located is mined, and a horizontal artificial false tunnel is constructed in the access road and a vertical steel cylinder (9) interface is reserved. In subsequent layers, the steel cylinder (9) is connected downwards section by section with the mining-filling cycle, and finally a through safe passage is formed.

5. The construction method according to claim 4, characterized in that: The horizontal artificial false alley includes retaining walls (2), I-beams (3), channel steel (4), steel base plates (5), triangular steel plates (12), back plates (13), and round logs (6).

6. The construction method according to claim 4 or 5, characterized in that... The specific steps include the following: S1: In the first mining layer, the adjacent access roads on both sides of the false roadway are mined and filled first. After the filling body on both sides reaches the design strength, the access road where the false roadway is located is mined again. The first section of steel cylinder (9) is erected at the design position in the access roadway. The crushed ore cushion layer (8) is laid at the bottom of the stope and a plastic film (10) is laid. Then the artificial false bottom (7) is constructed. After the artificial false bottom (7) is cured, a retaining wall (2) is constructed on the side of the steel cylinder (9) near the upper plate of the stope. The height of the steel cylinder (9) in the middle section of the first mining layer is greater than the sum of the thickness of the artificial false bottom (7) and the thickness of the crushed ore cushion layer (8). S2: On the artificial false bottom (7), install side and top I-beams (3) at the designed spacing, install steel pads (5) at the bottom of the I-beams (3) to improve stability, add back plates (13) on both sides and fill with round logs (6) for stability, install channel steel (4) between the side I-beams (3), and place back plates (13) and round logs (6) on the top plate of the I-beams (3); S3: Complete the overall filling of this layer to form a filling body (1) that encloses the false alley and steel cylinder; S4: Proceed to the next layer of mining, exposing the lower end of the steel cylinder (9) reserved in the previous layer, and reserve a movable ladder to connect to the safety exit; S5: After the mining is completed, clean the working face, connect and fix the new steel cylinder (9) of this section with the steel cylinder (9) of the previous section, lay a crushed ore cushion layer (8) at the bottom of the mining area, and lay a plastic film (10) before filling; S6: Repeat steps S4-S5 until the steel cylinder extends to the bottom layer.

7. The construction method according to claim 6, characterized in that: As each section of steel cylinder (9) is fixed together, a corresponding section of pedestrian ladder (11) is installed on the inner wall of that section of steel cylinder (9) and connected layer by layer with the previous section of ladder.

8. The construction method according to claim 6, characterized in that: Before each layer of filling construction, the welding and pre-reservation of the steel cylinder (9) of that layer are completed. After filling, its lower end interface is located in the crushed ore cushion layer (8). When the roof is exposed during the mining of the lower layer of ore body, the interface of 20~30cm is exposed.

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